This invention relates to torque sensing devices, particularly to those used to measure the torque output of a combustion engine. The torque measurement may be employed to control the output of the engine or balance the output of several parallel engines.
A well known method of determining torque is to sense the axial force produced on a helical gear transmitting the torque. A challenging design problem is to rotably support the gear to transmit the torque and provide low fractional resistance to axial movement in order that good sensitivity to torque changes are obtained. In addition the torque sensing device desirably should be able to operate for short periods of lubricating fluid supply failure without damage. Accordingly the object of this invention is to provide a torque sensing device which senses the torque reaction force on a helical gear with high sensitivity and is capable of operating without lubricating oil supply for short periods of time. Further objects of this invention are to provide a torque indicating device of high load capability and compactness.